Famed movie prop is likely to fetch a seven-digit sum when auctioned by Bonhams.

As movie stars go, this one's a bit short—about a foot tall—but in 1941 it played the title role in one of the most celebrated movies ever made. And on Nov. 25, the statue from The Maltese Falcon goes on the block in New York, where auction house Bonhams expects it to fetch a tidy "seven figure"...